But a few days later, Olivia was devastated to find her bike was missing. Someone had stolen it from her front porch.

"She was heartbroken," said Kristen – who decided to post a notice to her Facebook friends.

"If you know someone who suddenly had a brand new bike after last night, please contact me and I will arrange to pick it up," her post stated. "Please don't let someone get away with stealing a 10 year old's birthday present. My girl is heartbroken. Let's show her that someone will do the right thing."

The post spread, and eventually a teacher from Memorial Middle School in South Portland read it.

"I read about it during lunch, and it stewed in my mind," said eighth grade language arts teacher Jeremy LaRose. "Then during class, I said let’s do something about it. We are reading ‘To Kill a Mockingbird’ right now, and we’re learning about how one person can make a difference."

Mr. LaRose told his students about Olivia's bike. None of them knew her, but they said that didn't matter. LaRose said almost immediately, students began emptying their pockets.